For a quick and probably incomplete guide comparing the roll to stake to other roles that can One-Shot Torpor a Vampire. tl:dr staking is hard. Accomplishing the same effect on 1 roll using a method other than staking is in most circumstances harder.

So the minimum dice pool required to stake a vampire is 4(all 10s requires a messy critical) if the defense roll falls.

Now, if the goal is to torpor and not kill, dealing aggravated damage is a poor choice. Not only that, but it’s limiting. There are 5 discipline powers that allow a vampire to deal aggravated damage, so without it you’ll need a incendiary weapon. (pg 380) I’ll save you the time of looking it up and let you know that since they continue to burn the round after, they aren’t a reasonable way to OST. As far the 5 discipline powers 3 of them are level 5 (Fist of Caine, Baal’s Caress, and Cauldron of Blood) and 1 isn’t in the game (Touch of Oblivion). OST can be obtained with as low as 2 dice for each of those powers with a Messy Critical. This leaves a bite attack (2 aggravated damage pg 301 ) from someone using Feral Weapons (+2 brawl damage pg 270) Due to the set damage value of a bite, this would only require 1 success.

Non-Halved Superficial damage is slightly easier to obtain. With Feral Weapons as claws it can be done with the same 4 dice minimum required to stake, but can be accomplished without a Messy Critical (but still would require a critical and 2 more success + 2 claw damage) Scorpion’s Touch can also achieve this but with more dice, and would require the same to OST as staking.

Superficial damage requires obtained 16 damage before halving. The heaviest weapons gives +4 damage, so the roll needs to result in 12 successes to accomplish an OST. Minimum dice pool of 6 and requiring rolling all 10s to accomplish that. Decapitation is an easier roll.

One of the main advantages of staking is that the subjects health doesn’t matter. Sure a character with 1 stamina can probably be fairly easily subdued by a standard Gangrel, but a character at creation can potentially have 20 boxes ( Stamina 4 + 3 + Fortitude 3 w/Resilience) Regardless of how tanky the character is, the number of successes a staking needs doesn’t change.